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<pre><span class="sourceLineNo">001</span><a name="line.1"></a>
<span class="sourceLineNo">002</span>/*<a name="line.2"></a>
<span class="sourceLineNo">003</span> * Copyright (C) 2014 Archie L. Cobbs. All rights reserved.<a name="line.3"></a>
<span class="sourceLineNo">004</span> *<a name="line.4"></a>
<span class="sourceLineNo">005</span> * $Id: FilterFunction.html 743 2015-01-28 21:39:47Z archie.cobbs $<a name="line.5"></a>
<span class="sourceLineNo">006</span> */<a name="line.6"></a>
<span class="sourceLineNo">007</span><a name="line.7"></a>
<span class="sourceLineNo">008</span>package org.jsimpledb.parse.func;<a name="line.8"></a>
<span class="sourceLineNo">009</span><a name="line.9"></a>
<span class="sourceLineNo">010</span>import com.google.common.base.Predicate;<a name="line.10"></a>
<span class="sourceLineNo">011</span>import com.google.common.collect.Iterables;<a name="line.11"></a>
<span class="sourceLineNo">012</span>import com.google.common.collect.Sets;<a name="line.12"></a>
<span class="sourceLineNo">013</span><a name="line.13"></a>
<span class="sourceLineNo">014</span>import java.util.Map;<a name="line.14"></a>
<span class="sourceLineNo">015</span>import java.util.NavigableSet;<a name="line.15"></a>
<span class="sourceLineNo">016</span>import java.util.Set;<a name="line.16"></a>
<span class="sourceLineNo">017</span><a name="line.17"></a>
<span class="sourceLineNo">018</span>import org.jsimpledb.parse.ParseSession;<a name="line.18"></a>
<span class="sourceLineNo">019</span>import org.jsimpledb.parse.expr.AbstractValue;<a name="line.19"></a>
<span class="sourceLineNo">020</span>import org.jsimpledb.parse.expr.ConstValue;<a name="line.20"></a>
<span class="sourceLineNo">021</span>import org.jsimpledb.parse.expr.EvalException;<a name="line.21"></a>
<span class="sourceLineNo">022</span>import org.jsimpledb.parse.expr.Value;<a name="line.22"></a>
<span class="sourceLineNo">023</span><a name="line.23"></a>
<span class="sourceLineNo">024</span>@Function<a name="line.24"></a>
<span class="sourceLineNo">025</span>public class FilterFunction extends ApplyExprFunction {<a name="line.25"></a>
<span class="sourceLineNo">026</span><a name="line.26"></a>
<span class="sourceLineNo">027</span>    public FilterFunction() {<a name="line.27"></a>
<span class="sourceLineNo">028</span>        super("filter");<a name="line.28"></a>
<span class="sourceLineNo">029</span>    }<a name="line.29"></a>
<span class="sourceLineNo">030</span><a name="line.30"></a>
<span class="sourceLineNo">031</span>    @Override<a name="line.31"></a>
<span class="sourceLineNo">032</span>    public String getHelpSummary() {<a name="line.32"></a>
<span class="sourceLineNo">033</span>        return "filters a collection";<a name="line.33"></a>
<span class="sourceLineNo">034</span>    }<a name="line.34"></a>
<span class="sourceLineNo">035</span><a name="line.35"></a>
<span class="sourceLineNo">036</span>    @Override<a name="line.36"></a>
<span class="sourceLineNo">037</span>    public String getUsage() {<a name="line.37"></a>
<span class="sourceLineNo">038</span>        return "filters(items, variable, expression)";<a name="line.38"></a>
<span class="sourceLineNo">039</span>    }<a name="line.39"></a>
<span class="sourceLineNo">040</span><a name="line.40"></a>
<span class="sourceLineNo">041</span>    @Override<a name="line.41"></a>
<span class="sourceLineNo">042</span>    public String getHelpDetail() {<a name="line.42"></a>
<span class="sourceLineNo">043</span>        return "Creates a filtered view of an Iterable, where items are included only if when the item is assigned to the"<a name="line.43"></a>
<span class="sourceLineNo">044</span>          + " specified variable the specified expression evaluates to true. Maps are also supported, in which case the map's"<a name="line.44"></a>
<span class="sourceLineNo">045</span>          + " entrySet() is filtered.";<a name="line.45"></a>
<span class="sourceLineNo">046</span>    }<a name="line.46"></a>
<span class="sourceLineNo">047</span><a name="line.47"></a>
<span class="sourceLineNo">048</span>    @Override<a name="line.48"></a>
<span class="sourceLineNo">049</span>    protected Value apply(ParseSession session, final ParamInfo params) {<a name="line.49"></a>
<span class="sourceLineNo">050</span>        return new AbstractValue() {<a name="line.50"></a>
<span class="sourceLineNo">051</span>            @Override<a name="line.51"></a>
<span class="sourceLineNo">052</span>            public Object get(final ParseSession session) {<a name="line.52"></a>
<span class="sourceLineNo">053</span><a name="line.53"></a>
<span class="sourceLineNo">054</span>                // Build predicate<a name="line.54"></a>
<span class="sourceLineNo">055</span>                final Predicate&lt;Object&gt; predicate = new Predicate&lt;Object&gt;() {<a name="line.55"></a>
<span class="sourceLineNo">056</span>                    @Override<a name="line.56"></a>
<span class="sourceLineNo">057</span>                    public boolean apply(Object item) {<a name="line.57"></a>
<span class="sourceLineNo">058</span>                        return FilterFunction.this.evaluate(session, params.getVariable(),<a name="line.58"></a>
<span class="sourceLineNo">059</span>                          new ConstValue(item), params.getExpr()).checkBoolean(session, "filter()");<a name="line.59"></a>
<span class="sourceLineNo">060</span>                    }<a name="line.60"></a>
<span class="sourceLineNo">061</span>                };<a name="line.61"></a>
<span class="sourceLineNo">062</span><a name="line.62"></a>
<span class="sourceLineNo">063</span>                // Evaluate items<a name="line.63"></a>
<span class="sourceLineNo">064</span>                Object items = params.getItems().evaluate(session).checkNotNull(session, "filter()");<a name="line.64"></a>
<span class="sourceLineNo">065</span>                if (items instanceof Map)<a name="line.65"></a>
<span class="sourceLineNo">066</span>                    items = ((Map&lt;?, ?&gt;)items).entrySet();<a name="line.66"></a>
<span class="sourceLineNo">067</span><a name="line.67"></a>
<span class="sourceLineNo">068</span>                // Preserve NavigableSet if possible<a name="line.68"></a>
<span class="sourceLineNo">069</span>                if (items instanceof NavigableSet)<a name="line.69"></a>
<span class="sourceLineNo">070</span>                    return Sets.filter((NavigableSet&lt;?&gt;)items, predicate);<a name="line.70"></a>
<span class="sourceLineNo">071</span><a name="line.71"></a>
<span class="sourceLineNo">072</span>                // Preserve Set if possible<a name="line.72"></a>
<span class="sourceLineNo">073</span>                if (items instanceof Set)<a name="line.73"></a>
<span class="sourceLineNo">074</span>                    return Sets.filter((Set&lt;?&gt;)items, predicate);<a name="line.74"></a>
<span class="sourceLineNo">075</span><a name="line.75"></a>
<span class="sourceLineNo">076</span>                // Return Iterable view<a name="line.76"></a>
<span class="sourceLineNo">077</span>                if (items instanceof Iterable)<a name="line.77"></a>
<span class="sourceLineNo">078</span>                    return Iterables.filter((Iterable&lt;?&gt;)items, predicate);<a name="line.78"></a>
<span class="sourceLineNo">079</span><a name="line.79"></a>
<span class="sourceLineNo">080</span>                // Wrong type<a name="line.80"></a>
<span class="sourceLineNo">081</span>                throw new EvalException("invalid filter() operation on non-Iterable object of type " + items.getClass().getName());<a name="line.81"></a>
<span class="sourceLineNo">082</span>            }<a name="line.82"></a>
<span class="sourceLineNo">083</span>        };<a name="line.83"></a>
<span class="sourceLineNo">084</span>    }<a name="line.84"></a>
<span class="sourceLineNo">085</span>}<a name="line.85"></a>
<span class="sourceLineNo">086</span><a name="line.86"></a>




























































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